Monday, November 17, 2014

Map Monday: Mew Gull

1st-cycle Mew Gull from Mile Square Park, 1/1/12

I birded with Michael and Roger Woodruff yesterday. Twice I have birded with Michael; both instances involved date shakes (trust me, delicious!) and visits to the Salton Sea. Anyway, we found a Mew Gull at Tamarisk Lake at Desert Center. Happily unaware of the rarity of this species in the Riverside County deserts, we snapped a few mediocre photos without thinking too much of it. Turns out that it occurs once or twice per year in the county deserts--and usually at the Salton Sea. This sparked my curiosity about the bird's range.

The Desert Center Mew Gull, 11/16/14

Mew Gulls occur in the Eastern and Western hemispheres (though, there is disagreement about the status of the (sub)species--another one of those Green-winged/Common Teal conundrums). This map nicely illustrates their occurrence in Europe and North America--and it also illustrates the lack of coverage in Asia. It will be interesting to look at a map for this species in a decade or two once the eBird surge hits Asia.

Ah, North America. Like Varied Thrush last week, the Pacific Northwest seems to be the core of the reports. Records away from the Pacific Coast are scattered widely across the whole country.
Also, Mew Gull reaches the southern end of its (wintering) range in southern California (though, note the records from northern Baja and the Gulf of California--there would be more records if more people birded there. Perhaps it is not judicious to claim southern California represents the "southern edge" of ranges based on eBird maps. Hmm.)

Zooming in to California, we see that they stick pretty close to the coast, with the Salton Sea and the Central Valley the only places they wander far inland consistently. Closer to the coast (e.g., Los Angeles County, Orange County, western Riverside County) it consistently wanders inland a short distance, often frequenting small urban lakes.

1 comment:

Bob Kaufman said...

We saw a Mew Gull here in the Philippines last Dec. 31, 2013 in the northernmost province of Ilocos Norte. It was presumably of the kamtschatschensis subspecies.